1. Field of the Invention
The present invention relates to a stair exerciser and, more particularly, to an indoor cyclic stair exerciser having a plurality of revolvable steps supported by endless chain conveyors and a control device for speed control and arranged like an escalator, and which, by the weight and action of a user walking on the steps, enables the mechanism to run cyclical and continuous actions thereby affording the user stair climbing like exercises.
2. Prior Art
Many kinds of stair exercisers or treadmill exercisers are known, among these may be cited, for instance, the U.S. Pat. No. 3,497,215 to Harrison, et al, which discloses a stair exerciser consisting of stairs supported by endless chain conveyors and a hydraulic control system for control of the speed. Parsons' U.S. Pat. No. 3,592,466, like Harrison et al patent, teaches a stair exerciser consisting additionally of a device for adjusting the slope of the treadmill. The U.S. Pat. No. 4,687,195 to Potts, like Parsons' patent, discloses a treadmill exerciser having a mechanical speed control system and also the steps comprised of riser portion and tread portion are connected by hinges to each other to be at three points, that is, the chain side connecting ends of each of the riser portion and the tread portion and the connecting end of the riser portion and the tread portion are pivotable or foldable. The upper end of the riser portion of each step is connected by the afore-said hinges to the rear end of the tread portion of the same step while the lower end of the riser portion is connected by a hinge to the front end of the tread portion of the succeeding step. Next, in the U.S. Pat. No. 4,726,581, Chang discloses a stair exerciser similar to the one disclosed in Parsons' patent, but has cantilever-mounted steps.
In the steps used by Harrison and Parsons, the riser portion and the tread portion are formed that they are not foldable with respect to each other and this is thus disadvantageous to the drive of the chains. Although in Potts patent, the steps are mutually pivotable and foldable, owing to the use of three units of transversely long extended hinges to connect and fix each of the step members the construction is very complicated and the assembly is also inconvenient. Besides, the speed control system in Potts' treadmill exerciser is rather complicated and also requires hand manipulation and control. On the other hand, in Chang's patent because the steps are of a cantilever fashion the stability of support is not satisfactory.